Substrate integrated waveguide

Abstract

A substrate integrated waveguide ( 10 ) comprises a top conductive layer ( 14 ) and a bottom conductive layer ( 15 ) provided on either sides a substrate ( 11 ). At least one wall ( 12, 13 ) of conductive material is provided in the substrate ( 11 ) to define, together with the top and bottom layers ( 14, 15 ), the waveguide. The at least one wall ( 12, 13 ) comprise a multitude of thin conductive wires densely arranged close to each other in the substrate ( 11 ) and having respective short ends connected to the top and bottom layers ( 14, 15 ). The high number of wires per surface unit in the wall ( 12, 13 ) effectively prevent significant amount of power leakage through the wall ( 12, 13 ) during operation of the substrate integrated waveguide ( 10 ).

The invention claimed is: 
     
       1. A substrate integrated waveguide comprising:
 a top conductive layer; 
 a bottom conductive layer; 
 a supportive substrate; and 
 at least one wall of conductive material connected to said top conductive layer and said bottom conductive layer, wherein said at least one wall comprises a multitude of conductive wires arranged close to each other at a density of at least 10 4  wires/cm 2  and said multitude of conductive wires have an average diameter less than 10 μm. 
 
     
     
       2. The waveguide according to  claim 1 , wherein said density is at least 10 6  wires/cm 2 . 
     
     
       3. The waveguide according to  claim 1 , wherein said density is equal to or less than 10 12  wires/cm 2 . 
     
     
       4. The waveguide according to  claim 1 , wherein said density is from 10 7  to 10 10  wires/cm 2 . 
     
     
       5. The waveguide according to  claim 4 , wherein said density is from 10 7  to 10 9  wires/cm 2 . 
     
     
       6. The waveguide according to  claim 1 , wherein said top conductive layer is provided on a first side of said supportive substrate, said bottom conductive layer is provided on a second, opposite side of said supportive substrate and said multitude of conductive wires forming said at least one wall traverse through said supportive substrate and have respective first ends electrically connected to said top conductive layer and respective second, opposite ends electrically connected to said bottom conductive layer. 
     
     
       7. The waveguide according to  claim 1 , wherein said supportive substrate has a thickness of less than 500 μm. 
     
     
       8. The waveguide according to  claim 1 , wherein said top conductive layer and said bottom conductive layer have a respective thickness equal to or less than 20 μm. 
     
     
       9. The waveguide according to  claim 1 , wherein said multitude of conductive wires have an average diameter less than 5 μm. 
     
     
       10. The waveguide according to  claim 9 , wherein said multitude of conductive wires have an average diameter from 0.02 μm to 5 μm. 
     
     
       11. The waveguide according to  claim 10 , wherein said multitude of conductive wires have an average diameter from 0.2 μm to 3 μm. 
     
     
       12. The waveguide according to  claim 1 , wherein said top conductive layer and said bottom conductive layer independently comprise a conductive metal selected from copper, gold or silver, or a conductive alloy thereof. 
     
     
       13. The waveguide according to  claim 1 , wherein said multitude of conductive wires comprises a conductive metal selected from nickel, copper, silver or gold, or a conductive alloy thereof. 
     
     
       14. The waveguide according to  claim 1 , wherein said supportive substrate comprises a dielectric material selected from polyimide, polyethylene, polyethylene naphthalate, polyethylene terephthalate, liquid crystal polymer, polytetrafluoroethylene, perfluoroalkoxy, fluorinated ethylene propylene. 
     
     
       15. A method of producing the substrate integrated waveguide according to  claim 1 , said method comprising the steps of:
 irradiating at least a selected portion of a substrate with accelerated particles to form a multitude of tracks of damaged substrate material in said substrate; 
 forming capillaries in said substrate along said multitude of tracks by removing said damaged material; 
 selectively filling at least a portion of said capillaries with a conductive material to from said multitude of conductive wires traversing said substrate, wherein said multitude of conductive wires are arranged in said substrate to form said at least one wall of said substrate integrated waveguide; and 
 electrically connecting respective first ends of a multitude of conductive wires with a top conductive layer provided on a first surface of said substrate and respective second, opposite ends of said multitude of conductive wires with said bottom conductive layer provided on a second, opposite surface of said substrate. 
 
     
     
       16. The method according to  claim 15 , wherein said forming step comprises exposing said substrate to etching to form said capillaries in said substrate along said multitude of tracks. 
     
     
       17. The method according to  claim 15 , wherein
 said irradiating step comprises irradiating said at least a selected portion of said substrate with said accelerated particles to form said multitude of tracks of damaged substrate material traversing said substrate, and 
 said forming step comprises forming said capillaries through said substrate along said multitude of tracks by removing said damaged material. 
 
     
     
       18. The method according to  claim 17 , wherein said irradiating step comprises irradiating said at least selected portion of said substrate with accelerated ions having an average velocity and mass selected so that average kinetic energy of said accelerated ions is high enough that at least 80% of said accelerated ions fully penetrate through said substrate. 
     
     
       19. The method according to  claim 15 , wherein said selectively filling step comprises:
 coating said first surface of said substrate with a masking layer; 
 removing a selected portion of said masking layer to expose said at least a portion of said capillaries; and 
 filling said exposed said at least a portion of said capillaries with said conductive material. 
 
     
     
       20. The method according to  claim 15 , wherein said electrically connecting step comprises:
 providing said bottom conductive layer on said second, opposite surface of said substrate prior to selectively filling said at least a portion of said capillaries with said conductive material to allow said second, opposite ends of said formed multitude of conductive wires to become electrically connected to said bottom conductive layer during said selectively filling step; and 
 providing said top conductive layer on said first surface of said substrate following said selectively filling step to connect said first ends of said formed multitude of conductive wires with said top conductive layer. 
 
     
     
       21. The method according to  claim 15 , wherein said irradiating step comprises irradiating substantially the whole substrate with said accelerated particles to form a target porosity in said substrate by said multitude of tracks of damaged substrate material. 
     
     
       22. The method according to  claim 15 , wherein said selectively filling step comprises selectively filling said at least a portion of said capillaries with said conductive material to form said multitude of conductive wires traversing said substrate at a minimum density of at least 10 4  wires/cm 2 . 
     
     
       23. A substrate integrated waveguide comprising:
 a top conductive layer; 
 a bottom conductive layer; 
 a supportive substrate; and 
 at least one wall of conductive material connected to said top conductive layer and said bottom conductive layer, wherein said at least one wall comprises a multitude of conductive wires arranged close to each other at a density of at least 10 4  wires/cm 2  and said at least one wall consists of composite material in the form of dielectric material of said supportive substrate and conductive material of said multitude of conductive wires traversing through said supportive substrate, said conductive material constituting from 1 up to close to 100% of the volume of said composite material of said at least one wall.